1. Field of the Invention
The present invention relates to a recording tape cartridge, which contains a single rotatable reel around which a recording tape such as a magnetic tape is wound and when used, winds the recording tape onto the reel.
2. Description of the Related Art
A recording tape such as a magnetic tape is commonly employed as an external recording medium for devices such as a computer. A recording tape is contained in a recording tape cartridge. A recording tape cartridge typically has a recording tape with a leader member attached at the leading end portion of the tape, a reel around which the recording tape is wound, and a case housing the reel rotatably. Thus structured, little space is required when storing and in that space, a magnetic tape cartridge is able to record a large amount of information.
In order to record information to the recording tape cartridge, and to play back recorded information therefrom, the recording tape cartridge is loaded into a tape drive. When the recording tape cartridge is loaded into the tape drive, a take-up device of the tape drive takes up a leader member and takes guides it to the wind-up reel of the tape drive. When the leader member is guided to the reel, the recording tape is wound from the cartridge to the reel. Simultaneously, a read-write head preset along the tape path records information to (or plays it back from) the recording tape. Examples of common leader blocks include block-shaped leader blocks, small cylindrical leader pins, and tape-shaped leader tapes having a thickness greater than that of the recording tape.
The recording tape cartridge possesses a leader block that acts as a leader member. When the recording tape cartridge is used, the tape drive, which serves to secure the recording tape cartridge, unwinds the leader block and subsequently winds and secures said leader block to a reel hub. When the leader block is secured to the reel hub, the curved end of the leader block conforms to the shape of the outer periphery of the reel hub and forms the winding surface of the recording tape cartridge in the tape drive.
The smoothness of the wind-up surface of the reel hub of the tape drive depends on the dimensional accuracy of the leader block. However, because the leader block is attached to the recording tape cartridge, its dimensional accuracy differs from cartridge to cartridge and, as such, the tape drive is sometimes unable to compensate completely for the dimensional inaccuracy of the leader block. The size of the gap, which forms between the edge of the opening for securing the leader block and the surface of the leader block, also differs from cartridge to cartridge. This gap can result in a large bump on the wind-up surface.
This bump on the wind-up surface can also form creases or other deformations on a recording tape. Creases and deformations can also be formed on the second and upper layers of the recording tape including the recording areas. Running creased or deformed parts of the recording tape by the read-write head leads to deviation in the correct distance between the read-write head and the recording tape. These deviations can lead to the formation of unrecorded areas and loss of recorded information.
Additionally, it is necessary to widen the width of the entrance of the reel hub's storage section, which stores the leader block. For example, in a reel hub with a diameter of 50 mm, if the recording tape has a width of 12.7 mm then the opening in the outer section needs to be approximately 12 mm. If the dimensions of the leader block differ, then the height of the bump can differ greatly and the possibility of the aforementioned problems occurring increases greatly.
When utilizing a recording tape cartridge equipped with a leader pin as a leader member, the tape drive, which possesses an unwinding device, takes up the leader pin with its unwinding leader block. In the aforementioned tape drive, the take-up leader block hooks the leader pin and pulls it, thus winding up the recording tape. Then, the take-up leader block and the leader pin engage each other and are secured inside the reel hub of the wind-up reel. Thus, the curved end surface of the take-up leader block and the periphery of the reel hub form a wind-up surface on the reel hub. Accordingly, the bump formed on the surface of the wind-up surface is not influenced by changes in the dimension of the leader pin.
However, the position of the leader block is not usually configured to come into contact with the reel hub. Instead, it is configured so as to be movable inside of the reel hub when secured thereto, so as not to inhibit the movement of the cam mechanism of the take-up device, and further, to allow movement within the reel hub so that a pin can disengage from a through hole. The take-up leader block moves along a predetermined tape path, which is often a complicated path, by a plurality of cam mechanisms and arm mechanisms. Due to the complexity of the paths, an accumulation of mechanical inaccuracy of the various mechanisms can cause inaccurate positioning of the leader block inside the reel hub.
The inaccurate positioning of the take-up leader block can also lead to the formation of a gap on the wind-up surface of the reel hub, formed at the edge of the opening for securing the take-up leader and at the end surface of the take-up leader block. This gap causes the formation of creases and deformations on the recording tape.
On the other hand, when loading a recording tape cartridge equipped with a leader tape to a tape drive, a take-up leader fixed at one end to the reel hub picks up the leader tape at the other end of the recording tape. The leader tape and the recording tape of the cartridge are then wound onto the reel hub. Thus, the recording tape is wound over both the take-up leader and the leader tape onto the reel hub, and bumps on the reel hub surface do not create creases or deformations on the recording tape.
However, both the leader tape and the take-up leader have a greater thickness than the recording tape. In addition, the wind-up tape takes up the leader tape with the other end of the take-up leader inserted into a fixed opening of the leader tape, and then, both are taken up with the ends of each overlapped. While the overlapped portion does form a gap which can create a crease and a deformation, specific measurements can be taken and procedures implemented as needed to avoid the formation of a crease and deformation, for example, making the leader tape longer so it is able to wrap around the reel hub in several turns.